The Essential Turing: The Ideas that Gave Birth to the Computer Age

In one volume Jack Copeland has assembled the influential and historically significant papers, letters and radio broadcasts of Alan Turing (1912-1954). These include Turing's work on logic, digital computers, code breaking, artificial intelligence, and artificial life. Each source is preceded by an explanation of both the scientific details of the piece as well as its subsequent impact.

Reprinted in its entirety is Turing's 1936 paper "On Computable Numbers with an Application to the Entscheidungsproblem," in which he introduces the notion of a universal computing machine and offers a negative solution to Hilbert's decision problem (Entscheidungsproblem). This universal machine has evolved into what today is known as a complier or interpreter in computer science. Copeland includes the text of Turing's 1947 lecture on the Automatic Computing Engine (ACE), compares this with John von Neumann's work on the Electronic Discrete Variable Automatic Computer (EDVAC), and traces Turing's influence on the EDVAC.

Of particular importance is Turing's breaking of the German naval enigma code during World War II, shortening the war in Europe by what is estimated to be at least two years. Reprinted are several recently declassified documents, including excerpts from Turing's "Treatise on the Enigma," Patrick Mahon's account of code breaking at Bletchley Park, as well as a letter from Turing to Winston Churchill to secure additional support for code breaking. A fairly detailed account of the Steckerbrett (plug-board) enigma machine is given in what Turing calls "Bombe and Spider," a chapter from "Treatise on the Enigma."

Finally there appears Alan's work on artificial life and artificial intelligence from the papers "Computing Machinery and Intelligence," "The Chemical Basis for Morphogenesis," "Chess," and "Solvable and Unsolvable Problems." The latter contains an informal discussion of the decision problem and its significance, suitable for a lay audience. The book is organized chronologically with bibliographic references given as footnotes and suggestions for further reading appearing at the end of some chapters. Copeland includes a brief biography of Turing, although for more information about Turing's life and untimely death at his own hands, see Andrew Hodges' Alan Turing: The Enigma, cited at the end of the introduction.

Jerry Lodder received his doctorate in mathematics from Stanford University and has held assistantships at the Institut de Recherche Mathématique Avancée in Strasbourg and the Institut des Hautes Etudes Scientifiques in Paris. His interests include topology, geometry, the history of mathematics and mathematics education. Teaching from primary historical sources, he has introduced logic in a beginning discrete mathematics course via excerpts from Alan Turing's "On Computable Numbers, with an Application to the Entscheidungsproblem." Jerry enjoys traveling to other colleges and universities to discuss the use of history in teaching mathematics.